Ecology exam 2

In the comparison of seed sizes consumed by desert ants and rodents, which of the following statements is true?

Ants consumed smaller seeds than rodents.

According to the Lotka-Volterra model of predator-prey interactions, why do the populations of foxes and rodents cycle through periods of growth and decline?

As rodent numbers increase, predation rate by foxes also increases, which causes the rodent populations to decline.

A species' _____ is the range of abiotic and biotic conditions under which it lives.

realized niche

The carrying capacity of a population of birds in a small patch of forest is 100 individuals. Last year there were 20 birds living in this patch, and this year there are 35. Their population has an intrinsic growth rate of 1. The population grows according to a delayed density dependence model in which τ = 1 year. If the base year is 2014, in what year will the bird population first exceed its carrying capacity?

2018

Using mark-recapture techniques, you have estimated that there are 258 total grizzly bears on Kodiak Island, Alaska. During your initial sampling, you captured and marked 217 grizzlies, of which you recaptured 53 upon your second sampling. Approximately how many total grizzlies did you capture in your second sampling?

63

Which of the following statements is/are true regarding the interaction between sea urchins and algae in rocky shore communities?

Both algae biodiversity is higher when sea urchins are present, and the total algal biomass is lower when sea urchins are present.

Populations of collared lizards fluctuate over time as they approach and overshoot the carrying capacities of their habitats. In a metapopulation of collared lizards, how does decreasing the distance between habitat patches affect the synchrony of fluctuations among lizard subpopulations?

Dispersal is more frequent between nearby patches, so subpopulations fluctuate synchronously.

What does the parasitic flatworm Leuchloridium paradoxum do during the first stage of its life cycle to increase its chances of completing the second stage of its life cycle?

During the first stage of its life cycle, the flatworm changes the appearance of a snail's eyestalk and manipulates a snail's behavior to make the snail more conspicuous to a predatory bird in which a flatworm can reproduce and complete the second stage of its life cycle.

Which of the following statements is correct regarding the study concerning scale insects and parasitoid wasps?

Increasing the number of scale insects led to an increase in the number of wasps.

When a population is small there is an abundance of resources for all individuals, so the per capita resource availability is high, thus leading to more rapid growth rates (as compared to larger populations). Why then are small populations more likely to go extinct compared to large populations?

Small populations are more impacted by stochastic events.

Select the statements that explain why very small and very large populations experience slow population growth under the logistic growth model. choose all that apply

Small populations have fewer individuals capable of producing offspring. Limited resources are shared among many individuals in very large populations.

Why are parasites often more lethal outside of their native range?

The host population in the new region lacks defensive adaptations against foreign parasites

In terms of metapopulation modeling, what is a dispersal barrier?

Unsuitable habitat surrounding suitable habitat.

In a stream ecosystem, two species of aquatic plants rely on available nitrogen and phosphorus as nutrients. Under what conditions would these two species, in competition for two nutrient resources, be prevented from coexisting?

When one species is better able to persist at lower levels of nitrogen and phosphorus, while the other species requires high levels of both.When both species are able to persist at equivalent levels of nitrogen and phosphorus.When both species are able to survive at lower levels of nitrogen but require higher levels of phosphorus.

When examining a population's age structure, it is possible to estimate when the population experienced unusually high birth rates if _____.

a certain age group contains an unusually high number of individuals

Scientists believe that some species of eucalyptus in Australia promote frequent fires by means of flammable oils in their leaf litter. These fires kill completing plants. What type of competition does this example describe?

allelopathy

Warning colors, such as those displayed by monarch butterflies, are a defense strategy also known as _____.

aposematism

One reason organisms with large body sizes have higher survival rates is because they _____.

are better at maintaining homeostasis in the face of unfavorable environmental changes

Reduced growth and development due to reduced feeding and foraging activity is a cost of

behavioral defenses.

You began studying the population growth of an invasive aquatic weed on August 23, 2005, when the population contained 450 individuals. You monitored the population's abundance every year from 2006 through 2010, when the population had 1,550 individuals. On August 23, 2010, what was the approximate instantaneous rate of change of the invasive weed's population size?

dN/dt = 275 individuals per year

One problem associated with using a cohort life table instead of a static life table to estimate population growth is that you cannot _____.

disentangle environmental effects from age-related effects on life history traits

What is an example of a density-independent factor that might limit a population's growth?

drought

Ants should live in _____ populations, and rhinoceroses should live in _____ populations.

high-density; low-density

A potential host that has the ability to prevent a parasite infection from occurring is said to possess which of the following?

infection resistance

When long-legged ants plug the nest entrances of red harvester ants with which they compete for seeds, it is called

interference competition.

Consider four populations of island birds. Each island has a different carrying capacity, and the birds are subject to environmental and demographic stochasticity. Which population is LEAST likely to go extinct?

island 4, K = 1,200

The logistic growth model describes a maximum population size that is

limited by density-dependent factors.

Diseases such as HIV and African sleeping sickness can avoid the host's immune system by

making themselves undetectable.

Generally, populations contain the highest density of individuals _____

near the center of their geographic range

An age structure graph that appears rectangular in overall shape would likely see what in the future?

no change in population size

According to an S-I-R model, if a pathogen can kill its host, the

pathogen should increase in abundance until the hosts begin to die

Which of the following is an example of a resource in an ecosystem?

space

The effects of fire suppression on forests in the United States once dominated by longleaf pines could best be described as _____.

suppression of fire both reduced the number of fire-resistant plants in the community and allowed superior competitors that cannot tolerate fire to persist

According to Lotka and Voltera what information was required to calculate the change in population size of the predator over time (dP/dt)?

the efficiency rate of converting prey consumed into predator offspring

According to an ideal free distribution, individual organisms would be expected to move into low-quality habitat when

the per capita benefit of the low-quality habitat equals the per capita benefit of the high-quality habitat.

Which of the following are intracellular parasites?

viruses